Transitions - Support OCCLUDED -> GONE

If an occluded app is launched over a lockscreen that is dimissable,
then when the app is closed it should go to GONE state, and not back
to LOCKSCREEN.

Fixes: 270554348
Test: atest KeyguardTransitionScenariosTest
Change-Id: Id3fd42ff772e027dcdbce779efb04a23ebbecc99